Slate: The Scrotum Is Nuts
"Are Testicles External for Cooling, Galloping, Display, or Something Else?"
Natural selection has sculpted the mammalian forelimb into horses’ front legs, dolphins’ fins, bats’ wings, and my soccer ball-catching hands. Why, on the path from the primordial soup to us curious hairless apes, did evolution house the essential male reproductive organs in an exposed sac? It’s like a bank deciding against a vault and keeping its money in a tent on the sidewalk.
More: Are Testicles External for Cooling, Galloping, Display, or Something Else?